1. Field of the Invention
This invention relates to an apparatus for aligning, calibrating, and otherwise evaluating simulator scene displays. More particularly, it relates to such an apparatus which will execute a variety of alignment and calibration functions for flight and similar simulator scene displays. In particular, this invention relates to an apparatus which can be used to carry out the following specific calibrations and tests: display bore-sighting with respect to the design eye point (DEP) of a simulator; display scene horizon horizontality checks and adjustment; display scene image sharpness, i.e., optical quality; display scene illuminance and/or luminance at the design eye point; and display scene optical focus distance.
2. Description of the Prior Art
In order for an aircraft to be certified by the Federal Aviation Administration (FAA), the windshield must meet designated size, shape and orientation criteria. The FAA standards speak to the area of view that may be blocked by a centerpost and they specify a minimum "over-the-nose-vertical angle." These standards are referenced to a design eye point, DEP, a specific locus where the pilot's eyes are located when the pilot is seated in the cockpit.
Simulators are judged by their success in achieving realism. Thus, in a flight simulator all major visual design parameters are referenced to the DEP as accurately as possible. In a flight training simulator the X, Y and Z coordinates of the DEP are typically defined by marks on various shell ribs, struts and other surface members. When seated in the simulator, the pilot/trainee uses these marks to orient his eyes with respect to the scene display.
Sophisticated flight simulators often utilize multiple scene displays. In the past, evaluations of the displays relied on the use of multiple instruments, a separate instrument for each type of measurement to be performed. The necessity for precisely positioning the various instruments separately for each different evaluation that must be carried out with each of the several displays is both time consuming and error prone.
There is a need for measurement of total, integrated scene illuminance at the DEP; however, previously it has been customary to stop with a factory measurement of a small area on the face of the CRT.
The conventional way of positioning and aligning each visual scene display at which the pilot looks during a simulated flight and which portrays an impression of the real world is through the use of a theodolite or transit.
The patent of McCrum et al., U.S. Pat. No. 4,139,769, Feb. 13, 1979, reveals a technique for boresight alignment utilizing a collimated beam projector, a vidicon, and a plurality of mirrors. A variety of other alignment and collimating instruments and angle measuring devices are disclosed in the following issued U.S. patents:
U.S. Pat. No. 3,355,979, issued Dec. 5, 1967 to Wirtanen.
U.S. Pat. No. 3,486,826, issued Dec. 30, 1969 to Colvin et al.
U.S. Pat. No. 3,575,512, issued Apr. 20, 1971 to Baboz.
U.S. Pat. No. 3,649,122, issued Mar. 14, 1972 to Holtz.
U.S. Pat. No. 3,762,018, issued Oct. 2, 1973 to Myer.
U.S. Pat. No. 3,836,258, issued Sept. 17, 1974 to Courten et al.
U.S. Pat. No. 3,918,814, issued Nov. 11, 1975 to Weiser.
U.S. Pat. No. 3,966,328, issued June 29, 1976 to Wiklund.
U.S. Pat. No. 4,015,906, issued Apr. 5, 1977 to Sharon.
U.S. Pat. No. 4,191,471, issued Mar. 4, 1980 to Courten et al.
U.S. Pat. No. 4,330,212, issued May 18, 1982 to Miller.
A comprehensive instrument for carrying out a series of different optical measurements of a simulator has hitherto not been provided. A need therefore remains for further improvement for apparatus for aligning, calibrating, and otherwise evaluating optical systems, suitable for meeting the demanding requirements of simulator scene displays.